feat(plugins): qualify host VST3 chains and refresh the DAW gallery (phase 89)

docs/TRACK_INSERTS.md

@@ -65,3 +65,30 @@ Edits are prepared and undoable, with finite range validation. Internal sync
 parameters follow project tempo. This is mono amplitude blending; stereo track
 insert layouts, latency compensation and gapless live insert edits are future
 work. Editing stops transport before preparing the replacement plan.
+
+The CLI `xtc-check --inspect project.xtc` lists insert format, slot order,
+bypass/wet settings and missing binary references without loading plugins.
+VST3 processing supplies a fixed output-parameter sink (64 IDs, final point per
+ID/block) for plugins that emit meter/parameter notifications; notifications are
+not recorded or exposed as controls.
+
+Host qualification on 2026-11-06 used the installed Linux x86_64 ZamEQ2,
+ZamAutoSat and ZamDelay VST3 binaries under `/usr/lib/vst3`. All three were
+prepared together, rendered with nonzero finite output and exported to WAV.
+This verifies those default mono configurations, not arbitrary plugins or
+physical hardware. The repository fixtures cover LADSPA, CLAP, VST2 and VST3
+insert adoption and VST3 output notification bounds. Internal-plan allocation
+failure and callback guards, sanitizers, GUI/JACK lifecycle and install checks
+cover host ownership and cleanup.
+
+Reproduce focused verification with:
+
+```sh
+make BUILD_DIR=build/audio-editor test-track-fx test-gui-track-fx
+XTC_TEST_HOST_VST3=1 ./build/audio-editor/test_track_fx
+```
+
+The host opt-in requires the three named Zam bundles; the normal tests use
+internal devices and controlled fixtures. The screenshot tool's
+`XTC_CAPTURE_HOST_VST3=1` mode captures those real host plugins; see
+[screenshots/README.md](../screenshots/README.md).